A manufacturing process for a semiconductor device or a liquid crystal display device typically includes a film-forming process or a photolithography process to form a circuit pattern on a substrate such as a wafer or a glass plate. These processes use a spin treatment apparatus to subject the substrate to treatments such as a chemical treatment, a washing treatment, and a drying treatment.
The spin treatment apparatus performs a wet treatment by clamping the outer peripheral surface of a substrate, rotating the substrate with the axis of rotation being an axis perpendicular to the substrate at the center thereof, and supplying a treatment liquid (e.g., a chemical liquid or pure water) to the rotating substrate. This spin treatment apparatus includes an annular liquid receiver configured to receive the treatment liquid flying from the rotating substrate. This liquid receiver is provided at a predetermined distance from the outer peripheral surface (end surface) of the rotating substrate.
The liquid receiver needs to receive liquid flying from the end of the substrate and also needs to prevent the liquid that hits the wall surface of the liquid receiver from splashing back toward the substrate. To prevent droplets splashing back from the wall surface of the liquid receiver from returning to the substrate surface (liquid splash-back), the wall surface of the liquid receiver is placed away from the end of the substrate.
However, as described above, in order to place the wall surface (inner peripheral surface) of the annular liquid receiver away from the end of the substrate for prevention of the liquid splash-back to the substrate, the outer shape of the liquid receiver needs to be larger accordingly. This increases the size and the weight of the spin treatment apparatus. For this reason, a spin treatment apparatus which is small and light, yet capable of suppressing the liquid splash-back to the substrate is demanded.